Over the years, crude vegetable oils such as palm, palm kernel, rice bran, soy bean, sunflower, canola, rapeseed, cottonseed, safflower and corn oil have been identified as containing high levels of phytonutrients or constituents beneficial to human health. These beneficial constituents may include but not limited to tocopherols, tocotrienols, carotenoids and steroids.
Tocopherols and tocotrienols are valuable constituents of vegetable oils because of their abilities to act as antioxidants and to provide protection against cell damage in the brain, tumors and various types of cancers, as well as to assist in the rehabilitation of damaged cells. Unique molecular structure of the tocotrienols further imparts hypocholesterolemic characteristics, thereby helping to maintain a healthy cardiovascular system. Specifically, tocotrienols can help lower blood cholesterol level through cleansing of the arteries of accumulated cholesterol.
Carotenoids are natural pigments synthesized by plants imparting yellow, orange or red colour. Of all the carotenoids, alpha-carotene, beta-carotene and beta-cryptoxanthin are precursors to vitamin A (or retinol), or interchangeably known as provitamin A, serving as a source of vitamin A. Other carotenoids such as lutein, lycopene and zeaxanthin cannot be converted to vitamin A but they are still of special interest because they are good antioxidants.
Plant based sterols, on the other hand, are recognized for their abilities to block absorption of cholesterols and reduce blood cholesterol level. Because the plant sterols are nearly identical to the cholesterols, they compete with each other for absorption in the small intestines. However, plant sterols are poorly absorbed by humans and they appear to block the absorption of the dietary cholesterols, thereby reducing the blood cholesterol level, as well as the risk of coronary heart disease. Some research studies have also demonstrated that the plant sterols possess anti-cancer, anti-inflammatory, anti-atherogenic and antioxidant characteristics.
In view of the foregoing, it is desired to extract or recover these beneficial constituents from the crude vegetable oils. Numerous recovery techniques have been presented in the past, such as solvent extraction, solvent fractionation, ion exchange resin treatment and chromatography method. However, these techniques have several drawbacks, including low yield, substantial degradation of constituents throughout the process, use of carcinogenic organic solvent, etc. Accordingly, there exists a need for an improved method for recovery of tocotrienols/tocopherols, carotenoids and sterols from oils.
The present invention provides a process for isolating tocotrienols/tocopherols, carotenoids and sterols from crude oils, particularly palm oils and refined palm oil distillates, and simultaneously recovering glycerols and free fatty acids in form of esters. In order to further improve quality of the recovered/isolated components, either molecular distillation or neutralization is utilized to the present invention as a pre-treatment step so as to reduce fatty acid content in the crude oils prior to recovery of components. Consequently, it facilitates to produce higher yield of phytonutrient (based on purity and mass yield) and a cleaner starting material for downstream processes. More importantly, various oil compositions with high free fatty acid could be used in the present invention for recovery of phytonutrients, which imparts versatility to it as well as the type of oil used.